ASME MFC-7:2016 pdf free download

ASME MFC-7:2016 pdf free download.Measurement of Gas Flow by Means of Critical Flow Venturis and Critical Flow Nozzles.
static temperature of a gas: actual bulk temperature of the flowing gas.
3.2.2 Crltkal Flow Venturis
CFV exit plane: surface at the exit of the divergent section.
CFV inlet plane: surface at the entrance of the convergent section.
critical flow venturi: a flowmeter having a geometrical configuration with a constant curvature convergent section to a minimum cross-sectional area (i.e., throat) at which sonic conditions exist followed by a conical divergent section.
critical (or choked)flow: maximum flow for a particular venturi that can exist for the given upstream conditions; the flow that exists when the ratio of the downstream static pressure, P2. to the upstream absolute pressures, P0,. is such that the fluid velocity reaches sonic conditions at the throat. This condition is termed “choked” flow, and the flow is proportional to the inlet stagnation pressure.
critical pressure ratio: the ratio of the absolute static pressure at the CFV throat to the absolute stagnation pressure for which gas mass flow through the CFV is a maximum.
iriaxitnuni back pressure ratio: the ratio of the highest absolute CFV exit static pressure to the absolute CFV upstream stagnation pressure at which the flow becomes critical.
throat: the cross section of the CFV with minimum diameter.
3.2.3 Pressure Measurement
stagnation (or total) pressure of a gas: pressure that would exist in the gas if the flowing gas stream were brought to rest by an isentropic process. Only the value of the absolute stagnation pressure is used in this Standard.
static pressure of a gas: the pressure of the flowing gas, which can be measured by connecting a pressure gauge to a wall pressure tap. Only the value of the absolute static pressure is used in this Standard.
wall pressure tap: a hole drilled in the wall of a conduit, the inside edge of which is flush with the inside surface of the conduit.